The hypotheses tested in this study were that 1) the use of chronically stimulated latissimus dorsi muscle can augment cardiac function in a failing canine heart, and 2) intracoronary lidocaine infusion can produce a model of left ventricular dysfunction. The study used dogs that had latissimus dorsi muscle wraps of the left ventricle and were stimulated by a pacemaker synchronously with the heart beat. A method of producing profound depression of ventricular contractibility was used and found to be reproducible and reversible. The augmentation of cardiac power by the muscle was determined by serial hemodynamic and angiographic measurements with and without flap stimulation with and without coronary lidocaine infusion. The results showed no augmentation of left ventricular power under any condition. These data show that the experimental operation as now performed in patients lacks laboratory confirmation and a reassessment of efficacy is necessary.